<!DOCTYPE html>
<html lang="zn">
<head>
    <meta charset="UTF-8">
    <title>按钮练习</title>
    <style>
        a:link{
            display: block;
            width: 93px;
            height: 29px;
            background-image: url('./img/08/link.png');
        }

        a:hover{
            background-image: url('./img/08/hover.png');
        }

        a:active{
            background-image: url('./img/08/active.png');
        }

        /* 
            图片属于网页中的外部资源，外部资源都需要浏览器单独发送请求加载
                浏览器加载外部资源时是按需加载的，用则加载，不用则不加载
                像我们的练习，link会首先加载，而hover和active会在指定状态触发时才会加载
        */
    </style>
</head>
<body>
    <a href="javascript:;"></a>
</body>
</html>